1.Technical Field
The present invention relates to a process for manufacturing road vehicle tires.
2.Background Information
Road vehicle tires are normally produced by assembling a first stage carcass and second stage outer annular tread assembly together to form a green tire, which is normally stitched externally, after being inflated with compressed air to ensure adhesion of the first and second stages. The green tire is then cured in a curing mold and restored to ambient temperature by means of a final post-inflation process.
The above method, which is currently employed by the majority of manufacturers, clearly provides in no way for in-process control of the external shape of the green tire. The absence of such control is responsible for most of the major defects encountered in finished tires currently available on the market, such as axial and radial dissymmetry, which are mainly caused by no control being effected for the position of the bead portions in relation to the outer tread portion.
Defects of this sort remain even after curing, despite forming the tire at relatively high temperatures against the surface of a mold negatively reproducing the outer surface of the finished tire. Each finished tire, retains not only any existing structural defects, but also stresses deriving from the shape memory of the tire components, which distort the tire slightly subsequent to removal from the curing mold and post-inflation.